1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to an image scanner, and more particularly, to a method and apparatus capable of effectively removing or suppressing show-through that may occur during scanning of a medium using an image scanner.
2. Description of the Related Art
An image scanner (hereinafter, referred to as ‘scanner’) may optically scan a medium, such as a document, a drawing, a photograph, or a film, obtain image data from light reflected by or transmitted through the medium using an image sensor, and process the image data in various ways.
In general, scanners may be classified into a complementary-metal-oxide-semiconductor (CMOS) image sensor (CIS) type or a charge-coupled device (CCD) type.
For the CIS type, red, green and blue (RGB) light may be irradiated onto a medium disposed on a glass plate in a predetermined temporal sequence, reflected by the medium, and then detected by photo-transistors. For the CCD-type, light irradiated from a lamp may be reflected by the glass plate with the medium, passed through an aperture, reflected by a mirror and then detected by a CCD linear array. The CIS and CCD types may be used as scanners or multifunctional apparatuses.
Meanwhile, when a thin or diaphanous medium, such as newspapers or printing paper, is scanned, not only intended data on a front surface of the medium but also unintended data on a rear surface thereof may be obtained during a scanning operation. This phenomenon is called ‘show-through’.